The interaction of actin and myosin in non-muscle systems as well as in skeletal muscle are regulated by several mechanisms. These include Ca2plus sensitivity via a troponin-tropomyosin system, phosphorylation of light chains associated with the myosin and interaction of actin with other associated proteins. The objectives of this proposal are to study these regulatory systems as they apply to nervous tissue actin and myosin. The regulatory proteins will be isolated from bovine brain. Their interactions with muscle and brain actin and myosin will be measured by MgATPase activity. Phosphorylation of the brain myosin will be studied and the associated kinase and phosphatase identified. The effect of phosphorylation on ATPase activity will be evaluated.